Heating systems for industrial furnaces, which indirectly heat the furnace inner chamber using radiant heat, are well-known. For this purpose, radiant-heating pipes are often utilized that are typically constructed as a one-sided open pipe or as a U-pipe and a fuel is burned with combustion air using a burner in hollow inner chamber thereof. The furnace chamber can be uniformly heated by a series of several such radiant-heating pipes or U-pipes.
In the alternative, so-called recuperator burners also are utilized, in which the heat from exhaust gases is used for pre-heating the combustion air. For this purpose, a burner and a recuperator are attached to a radiant-heating pipe. A portion of the exhaust gases flowing back into the radiant-heating pipe is utilized for pre-heating the fresh air. The heat exchange takes place in the recuperator. For example, a recuperator burner of LBE Feuerungstechnik GmbH/Germany is known under the trademark ECOMAX®. Such burners are utilized in direct- and indirect- (using radiant-heating pipes) heated industrial furnaces. By using recuperator burners, considerable energy savings can be realized in accordance with the burner model and the operating method.
For the sake of completeness, reference is made to DE 299 23 473 U1 and DE 41 13 412 C2, in which recuperator burners are disclosed, and moreover to DE 29 20 902 A1, in which a device for heating an industrial furnace is generally described.